Mold clamping device



Feb. 26, 1952 J. A. NELSON MOLD CLAMPING DEVICE Filed Dec'. 24, 1949 INVENTOR JOHN A.-NEON ATTORNEYS.

Patented Feb. 26, 1952 John A. Nelson, `VSt. .Petersburg F1a., assignor 'to Olin Industries, Inc., East Alton, Ill., 4a. corpora'tion of Delaware Application December'24, 1949,'5S'eralNm134j9i10 i 1 Claim.

This invention relates to permanent :metal molds for `the casting of metals, :and particularly Ato Water-cooled vertical elongated slab molds used for the casting vof copper `and its alloys in a form suitable for reduction to `sheet vstock by rolling; and particularly to thezmeans for clamping the separable .halves of the mold together.

Permanent -molds of this type consist of two elongated vertical members, one of which is stationary and constitutes the back, and the other of which is hingedly supported on one side of the .back and constitutes the front, of a split mold. 'Ihe mold front is complementary to the stationary mold back, and when the two parts are brought together they dei-lne. betweenthem, a vertically elongated rectangular chamber or mold cavity. To prevent separation of the front and back of the split mold, these members are .held together by some means of clamping which heretofore, in this type of mold, has consisted of a series of spaced yokes, each in combination with a manually operated jack screw. The .series of yokes and jack screws extend in spaced relation for the entire height of the mold.

In such molds of the heretofore customary construction, because of inability to obtain Acontrolled equal clamping pressures by means of the manually operated jacks employed, stress concentrations in the face plates lead to warping of these plates, necessitating removal and replacement at frequent intervals. This is believed due to excessive clamping forces atsome portions along the elongated mold, accompanied .by insuiiicient clamping forces at other portions, laggravating the tendency of the face plates to deform permanently during thermal expansion and contraction. Although the frame portions of the mold are rigid members relative to the face plates and side bars, there is flexure of the frames in the longitudinal direction, because of the elongated geometry of the mold and because of the tremendous forces caused by expansion and contraction ofthe face plates undergoing temperature changes, ranging Afrom that "of the cooling fluid to nearly that Aof the molten metal.

The object of the present invention, generally stated, is to provide a slab mold of the character .referred to wherein the useful life of .the face plates is extended.

A more specific object of lthe .invention .is to provide .amold of -thecharacter-referred to wherein the clamping pressures between the mold halves, when closed, are uniform throughout the contiguous parts thereof.

Other objects will become apparent to those (Cl. Z2-156) .2 skilled in the fart when the following description lread in .connection with the accompanying drawings,.:-in which:

Figurei .is a vyiew inside elevation of a slab mold constructed in .accordance with the present invention;

Fig-ure 2 is .a sectional view taken along line 2v-2 of Figure 1,; :and Y 'Figure 3 .is a perspective view, .showing the lower ,portionof the mold illustrated in AFigures 1 and 2, when in its opened position.

In accordance with the `present invention, .means `is provided for'clamping the .mold halves 1in closed position, such 'means being of =a character .such 'as to requalize the pressures exerted :between'the mold .halves over the entire periphery of their contiguous areas. Such equalizingmeans -preferably 'takes :the 'form of a plurality .of .fluidenergized jacks, connected to a common source of uid lunder pressure. ySuch an arrangement `assures uniformity ofthe mold .holding pressures,

not only prior to casting, but during the pouring and .fsolidication of the casting. Internal 'stresses Ydeveloped in-the .mold during the pouring of 4the metal, and' in 'both the mold and casting during Vsolidiiication of the casting, `are lautomatically relieved, so that replacement of lthe face `plates is .required at less frequent .intervals .than has heretofore lbeen necessary.

In Vthe embodimentf'illustrated in the drawings, the :mold .comprises a .mold back |00, which .ris stationary. and .a substantially complemented mold front illi, whiclili's movable relative to `the mold back. The :partei/.IUD and lill are hingedly .connected together by pairs of brackets l `and pivot pins 2. .The nflold 'back IUD has .a face plate -4 dening one side -of the mold cavity, .and the `mold front vl-0Iy as Va corresponding face plate 9. Arranged .bey/een the faceplates `4 and 9 is :a `pair :of side .pices 5 and 6 which define fthe :edges of the irnol'd cavity.

The side pieces 5 and l are connec-ted to one v4'of 'the .mol-d gparts, ,preferably the .stationary .back `I (I0, and :likewise the mold lback '|00 `(or the mold front, ,if desired) .is :provided with a bottom bar "l, which defines the bottom of the mol-d cavity.

The mold 'back 109 comprises .a hollow rectan- .fgular frame 3, openat one side, and vprovided at -one .end with .'a bracket or foot 24 for mounting the mold .back erectly. The face plate 4, usually -of copper, is .islidably :secured 4to the frame :to `cover the open :side of the frame. Side pieces .5 and B are detachably secured on the lateral edge portions of that surface on the face plate 4, which faces away from the frame. The bottom bar 'I is likewise detachably secured to the bottom portion of the surface of the face plate. The movable mold front IOI similarly comprises a heavy casting or frame 8. having a cavity open at one side, and covered by .face plate 9. which is detachably secured to the frame by any suitable means such as the series of bolts passing through slots at the edge portions of the face plate 9, as is face plate 4. The hollow cavity of the stationary frame 3, together with the plate 4, provides a cooling compartment l0. Similarly, the cavity of the movable mold front IBI provides a cooling compartment II. BothV the front and back of the mold are provided with 'appropriate'- conduits for the admission of a cooling medium, such as water, to the bottom of each cooling compartment I0 and II. Each compartment is also provided with an appropriate means for withdrawing the cooling medium from the top of the compartments. When the mold front and back are swung into contact, the water cooled face plate of each provides one face of an elongated rectangular vertical mold cavity I2, open at the top. The structure of the mold thus far specically described is conventional.

In accordance with the present invention, the means for clamping the mold halves VAtogether comprises a plurality of vertically' spaced yokes I3, slidably received in brackets I4 on the .outer surface of the mold front |0I, and' extending horizontally across the outer face thereof. Associated with each yoke is a pair of links I5, one end of each of which is pivotally attached to the yoke I3 at the respective ends thereof. Each link I5 has a shank portion, the free end of which consists of an enlargement or head |50, adapted to engage with one of the slotted lugs I6 extending laterally from the sides of the frame 3 of the mold back |00, when the adjacent portion of the shank is swung into the slot. Mounted onthe center of each yoke I3 is a :fluid operated ram I'I, having a plunger |10 adapted to be forced toward the frame 8. Fluid pressure to each ram is supplied through a flexible conduit I8, the

opening of which is controlled by a normally open valve |9. Each of the flexible conduits I8 is connected to a header pipe 20, whichA makes connection through a conduit 22 with the high pressure side of a suitable iiuid pump, not shown. A three-way master valve 2| selectively controls vthe ilow of uid from conduit 22 to header 20,

or from the latter to exhaust conduit 23. Inia pneumatically operated system, the conduit 23 'may exhaust to the atmosphere, but in a liquid operated system, the conduit' 23 extends back to the low pressure side of the pump.

In preparation for the operation of casting an elongated metal slab, the surfaces which form the mold cavity are rst dressed with any suitable mold coating material, such as a mixture of oil and graphite. The movable mold front |0I is swung toward the mold back |00, placing the face plate 9 in contact with the side pieces 5 and 6, and the bottom bar of the mold cavity. Each link I5 is then swung toward the mold back |00 until the shank passes through the slot Aof the mating lug I6, with the `heads |50 thereof behind the corresponding lugs. As a nal step in the closing of the mold, the valve 2| is actuated to connect the high pressure conduit 22A with all the rams. I1 simultaneously. When the pressure is brought up to a value suitable for 4 holding the mold parts, the master valve 2| is closed to retain the pressure on all the rams during the casting operation.

Before molten metal is poured into the mold cavity, a cooling medium, such as water, is admitted to the cooling compartments, and the ow of water is continuous through the compartments until the casting operation completed.

On receiving the charge of the molten metal poured into the open top of the mold cavity, local areas of the expanse of the cooled face plates undergo large and unequal changes in temperature, giving rise to stress concentrations in the face plates. Since the several rams I'I are connected together through the header 20, the pressure exerted at one locus of the mold will be equalized in the system, and consequently slight relative movement of the mold parts may take place to automatically relieve local stresses, and yet maintain uniform clamping pressure at all of the yokes I3.

After the slab has solidied, the master valve 2| is moved to the position whereat the header pipe 20 is connected to exhaust pipe 23, thereby relieving the pressure upon the several rams I1, and permitting the links` I5 'to be disengaged from their corresponding lugs I6. Thereupon, the mold parts |00 and |0| may be swung'open. and the casting removed.

From the` foregoing description it should be apparent that the present invention accomplishes its objects, and provides a mold of the character described wherein the -mold parts are held clamped together under uniform pressure,l and any localized increase in pressure is immediately equalized by interflow of pressure iluid from one ram to another.

l. While one complete embodiment of the invention has been described in detail, it is apparent that many modications thereof will present themselves to those skilled in the art, without 4departing from the spirit of the invention or the scope of the appended claim.

Having thus described the invention, what is claimed and desired to be secured by Letters Patent is:

An ingot mold comprising two face plates with side bars and a bottom bar therebetween delining a mold cavity open at the top, a pair of `hinged frames contacting the back surfaces of the respective face plates, yokes distributed unil`forrnly throughout the length of said frames, said yokes being carried by one o'f said frames and engageable with the other, a fluid operated ram mounted in each of said yokes and single means for operating all of said rams to apply pressure vuniformly v throughout the length of said face plates.

JOHN A. NELSON.

REFERENCES CITED I yThe following references are o record in the file of this patent:

UNITED STATES PATENTS 2,428,660 Falk Oct. 7, 194? 

